By default, if Data ONTAP encounters media errors during a RAID reconstruction, it automatically invokes an advanced mode process (wafliron) that compensates for the media errors and enables Data ONTAP to bypass the errors.
If the wafliron process is successful, RAID reconstruction continues, and the aggregate in which the error was detected remains online.
If the wafliron process fails or has been disabled, Data ONTAP attempts to place the affected aggregate in restricted mode. If this attempt fails, the storage system panics. After a reboot, Data ONTAP brings up the affected aggregate in restricted mode.
In restricted mode, you can manually invoke the wafliron process in advanced mode, or you can schedule downtime for your storage system by running the WAFL_check command from the Boot menu. You can disable the wafliron process by using the raid.reconstruction.wafliron.enable option. However, you are advised to leave the process enabled.